British firms are fearful of proposed European Union pension reforms that may require them to put billions of pounds into defined benefit pension plans, potentially spurring a trend to end such schemes, a survey showed Monday.

More than two thirds of the businesses polled said they were worried by the proposals, according to a survey of 160 firms by the Confederation of British Industry (CBI) employers' lobby group and investment consultancy Towers Watson.

The European Commission, the EU's executive body, has proposed that defined benefit schemes - which promise staff a pension based on their salaries - should be subject to stricter solvency rules, similar to those applied to insurance companies.

This would increase the funding targets for such pension schemes and reduce the length of time companies have to cover any shortfall in the funds backing the plans.

Pensions Minister Steve Webb said last week the EU reforms could cost British companies 100 billion pounds and vowed to fight the proposals, according to media reports.

CBI Chief Policy Director Katja Hall said the Commission was refusing to listen to the concerns of companies, who were already closing defined benefit scheme because of the rising costs of funding them.

What's completely unacceptable is Brussels' plan to impose further costs on firms operating defined benefit pensions at a time like this, when the protection in place has already proven itself during the economic crisis, she said.

The survey found two thirds of firms were worried the increasing expense of supporting their schemes would leave them with less room to invest in their business.

As a result a majority (64 percent) of those companies still providing defined benefit schemes were either planning to close their schemes completely or make changes to it within the next two years, the survey said.

Active membership of private sector defined benefit schemes in Britain fell to 2.1 million last year from 3 million in 2006, according to the Office for National Statistics.

(Reporting by Philip Baillie; Editing by Tim Castle/Ruth Pitchford)